*{
    margin:0;
    padding:0;
}

html,body{
    width:100%;
    height:100%;
    overflow: hidden;
}

#app{
    width:100%;
    height:100%;
    overflow: hidden;
    display: flex;
    flex-direction: column;
}

header,footer{
    width:100%;
    height: 44px;
    background: pink;
    flex-shrink: 0;
}

.con{
    width:100%;
    flex:1;
    overflow: hidden;
    &>div{
        position: relative;
        &:before{
            content:attr(up);
            width:100%;
            height: 44px;
            background: red;
            color:#fff;
            position: absolute;
            bottom:-44px;
            left:0;
        }
    }
}

ul li{
    widows: 100%;
    height: 60px;
    border-bottom:1px solid gray;
}